<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
<script>
    let str = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
   
    let cites = [
        { py: 'beijing', name: '北京' },
        { py: 'alishan', name: '阿里山' },
        { py: 'beidaihe', name: '北戴河' },
        { py: 'shijiazhuang', name: '石家庄' },
        { py: 'taiwan', name: '台湾' },

        
    ]
   
         let datas = {
        
           }
        for(let  i =0;i<str.length;i++){
            datas[str[i]] = []
            cites.forEach(function(item,index,array){
           let up = item.py[0].toUpperCase ()
            //    console.log(up)
           if(up == str[i]){
            datas[str[i]].push(item)
           
        }
       
        })
        }
        
         console.log(datas)
    
     </script>
    
</body>
</html>